Power loss from hole shot 175 Mariner (1993)

[Garrick]

I have been having problems on my boat. When hooked up to a Dyno machine at the marina it runs great all numbers match even when we put on a huge load. Once in the water when I floor it it pins at 2500 rpms and holds for a longtime and will not plane like it use too. I use to be able to pull skiers no problem and now I can barely get it to plane until I start messing with the trim and jackplate for about 3mins. Never had this problem before and have been running this etup for 3 years. What could the problem be. I took it to 2 mechanics and who also called master tech at Mercury and no knows what the problem is? Maybe I should just scrap it and claim it on my insurance. ANy help would be appreciated<br /><br />Thanks<br />Garrick

 

[chumbucket]

Re: Power loss from hole shot 175 Mariner (1993)

Fuel vent plugged ??? Exhaust restriction? Did you try 6 gal tank instead of your main tank?

 

[BassScratcher]

Re: Power loss from hole shot 175 Mariner (1993)

I had a similar problem on my 93 200 Mariner. Turned out to be a bad switchbox.

 

[ob]

Re: Power loss from hole shot 175 Mariner (1993)

Garrick , When you had motor dyno'd was the motor cover on or off? I'm thinking exhaust leak.Also, don't rule out gummed carbs.When running out of water,(no head on exhaust) motor will run with less effort.

 

[Garrick]

Re: Power loss from hole shot 175 Mariner (1993)

The cover was off.<br />I did not try the gas tank, But the breather for the gas tank which I am assuming is that metal thing on the back of my boatdoes spit out gas when I fill er up so does hat rule out that?<br />What does a switch box do? Curious.<br />I was also told that it could be my stator.<br /><br />Why wouldn't a mechanic find this out ecspecially a master tech?

 

[ob]

Re: Power loss from hole shot 175 Mariner (1993)

Garrick , If looking for performance issue problems a "master tech" would know enough to rule out exhaust leak and dyno with cowling on.Also, something is wrong .We have established that.All posters are also at disadvantage in not being able to see or touch motor.We are solely at the mercy of the problem input data.You can rule out ignition suspicions by performing spark test on all cylinders.Spark should jump 7/16 gap on all with bright blue spark.Master tech should have also ruled ignition out.Compression test?Anti syphon valve on tank fitting?Was dyno test performed using your fuel tank?Was motor run with old gas before problem surfaced?Have carburetors been cleaned and inspected?Carb linkage?Rule out one possible cause at a time or problem solving will become a crapshoot.

 

[SJ Striper]

Re: Power loss from hole shot 175 Mariner (1993)

Look for water in the fuel. Similar problem on Yamaha, checked everything, turned out to be water.